Use a large icing nail:
grease and line tin as normal
now place the nail flat side on the base of the tin and pour the cake mixture on top of the nail with the ‘long bit’ going into the mixture
When cake is ready leave it in the tin for 5 minutes then turn out and remove the screw.
Now leave the cake to cool properly.
You won’t notice the screw holes but they have helped the cake to cook right through